Dragons was the theme. There were letters from the Cavern Club Exhibitions Committee and the Friendly Flamethrowers League. There were pamphlets and appeals from the Sunshine Sanctuary for Sick Dragons- “Poor little VINNY's fires were nearly Damped after Five years' Cruel Use as a Paint-Stripper, but now-” And there were requests for donations, and talks, and things that added up to a heart big enough for the whole world, or at least that part of it that had wings and breathed fire.

If you let your mind dwell on rooms like this, you could end up being oddly sad and full of a strange, diffuse compassion which would lead you to believe that it might be a good idea to wipe out the whole human race and start again with amoebas.

Beside the drift of paperwork was a book. Vimes twisted painfully and looked at the spine. It said: Diseases of the Dragon, by Sybil Deidre Olgivanna Ramkin.

He turned the stiff pages in horrified fascination. They opened into another world, a world of quite stupefying problems. Slab Throat. The Black Tups. Dry Lung. Storge. Staggers, Heaves, Weeps, Stones. It was amazing, he decided after reading a few pages, that a swamp dragon ever survived to see a second sunrise. Even walking across a room must be reckoned a biological triumph.

The painstakingly-drawn illustrations he looked away from hurriedly. You could only take so much innards.

There was a knock at the door.

“I say? Are you decent?” Lady Ramkin boomed cheerfully.

“Er-”

“I’ve brought you something jolly nourishing.”

Somehow Vimes imagined it would be soup. Instead it was a plate stacked high with bacon, fried potatoes and eggs. He could hear his arteries panic just by looking at it.

“I've made a bread pudding, too,” said Lady Ramkin, slightly sheepishly. “I don't normally cook much, just for myself. You know how it is, catering for one.”

Vimes thought about the meals at his lodgings. Somehow the meat was always grey, with mysterious tubes in it.

“Er,” he began, not used to addressing ladies from a recumbent position in their own beds. “Corporal Nobbs tells me-”

“And what a colourful little man Nobby is!” said Lady Ramkin.

Vimes wasn't certain he could cope with this.

“Colourful?” he said weakly.

“A real character. We've been getting along famously.”

“You have?”

“Oh, yes. What a great fund of anecdotes he has.”

“Oh, yes. He's got that all right.” It always amazed Vimes how Nobby got along with practically everyone. It must, he'd decided, have something to do with the common denominator. In the entire world of mathematics there could be no denominator as common as Nobby.

“Er,” he said, and then found he couldn't leave this strange new byway, “you don't find his language a bit, er, ripe?”

“Salty,” corrected Lady Ramkin cheerfully. “You should have heard my father when he was annoyed. Anyway, we found we've got a lot in common. It's an amazing coincidence, but my grandfather once had his grandfather whipped for malicious lingering.”

That must make them practically family, Vimes thought. Another stab of pain from his stricken side made him wince.

“You've got some very bad bruising and probably a cracked rib or two,” she said. "If you roll over I'll put some more of this on.'' Lady Ramkin flourished a jar of yellow ointment.

Panic crossed Vimes's face. Instinctively, he raised the sheets up around his neck.

“Don't play silly buggers, man,” she said. "I shan't see anything I haven't seen before. One backside is pretty much like another. It's just that the ones I see generally have tails on. Now roll over and up with the nightshirt. It belonged to my grandfather, you know.''

There was no resisting that tone of voice. Vimes thought about demanding that Nobby be brought in as a chaperon, and then decided that would be even worse.

The cream burned like ice.

“What is it?”

“All kinds of stuff. It'll reduce the bruising and promote the growth of healthy scale.”

“What?”

"Sorry. Probably not scale. Don't look so worried.

I'm almost positive about that. Okay, all done." She gave him a slap on the rump.

“Madam, I am Captain of the Night Watch,” said Vimes, knowing it was a bloody daft thing to say even as he said it.

“Half naked in a lady's bed, too,” said Lady Ramkin, unmoved. “Now sit up and eat your tea. We've got to get you good and strong.”

Vimes's eyes filled with panic.

“Why?” he said.

Lady Ramkin reached into the pocket of her grubby jacket.

“I made some notes last night,” she said. “About the dragon.”

“Oh, the dragon.” Vimes relaxed a bit. Right now the dragon seemed a much safer prospect.

“And I did a bit of working out, too. I'll tell you this: it's a very odd beast. It shouldn't be able to get airborne.”

“You're right there.”

“If it's built like swamp dragons, it should weigh about twenty tons. Twenty tons! It's impossible. It's all down to weight and wingspan ratios, you see.”

“I saw it drop off the tower like a swallow.”

' 'I know. It should have torn its wings off and left a bloody great hole in the ground,“ said Lady Ramkin firmly. ”You can't muck about with aerodynamics. You can't just scale up from small to big and leave it at that, you see. It's all a matter of muscle power and lifting surfaces."

“I knew there was something wrong,” said Vimes, brightening up. “And the flame, too. Nothing goes around with that kind of heat inside it. How do swamp dragons manage it?”

“Oh, that's just chemicals,” said Lady Ramkin dismissively. “They just distill something flammable from whatever they’ve eaten and ignite the flame just as it comes out of the ducts. They never actually have fire inside them, unless they get a case of blowback.” “What happens then?”

“You're scraping dragon off the scenery,” said Lady Ramkin cheerfully. “I'm afraid they're not very well-designed creatures, dragons.” Vimes listened.

They would never have survived at all except that their home swamps were isolated and short of predators. Not that a dragon made good eating, anyway-once you'd taken away the leathery skin and the enormous flight muscles, what was left must have been like biting into a badly-run chemical factory. No wonder dragons were always ill. They relied on permanent stomach trouble for supplies of fuel. Most of their brain power was taken up with controlling the complexities of then- digestion, which could distill flame-producing fuels from the most unlikely ingredients. They could even rearrange their internal plumbing overnight to deal with difficult processes. They lived on a chemical knife-edge the whole time. One misplaced hiccup and they were geography.

And when it came to choosing nesting sites, the females had all the common sense and mothering instinct of a brick.

Vimes wondered why people had been so worried about dragons in the olden days. If there was one in a cave near you, all you had to do was wait until it self-ignited, blew itself up, or died of acute indigestion.

“You've really studied them, haven't you,” he said.

“Someone ought to.”

“But what about the big ones?”

“Golly, yes. They're a great mystery, you know,” she said, her expression becoming extremely serious.

“Yes, you said.”

“There are legends, you know. It seems as though one species of dragon started to get bigger and bigger and then . . . just vanished.”

“Died out, you mean?”

“No . . . they turned up, sometimes. From somewhere. Full of vim and vigour. And then, one day, they stopped coming at all.” She gave Vimes a triumphant look. “I think they found somewhere where they could really be. ”

“Really be what?”

“Dragons. Where they could really fulfil their potential. Some other dimension or something. Where the gravity isn't so strong, or something.”

“I thought when I saw it,” said Vimes, “I thought, you can't have something that flies and has scales like that.”

They looked at each other.

“We've got to find it in its lair,” said Lady Ramkin.

“No bloody flying newt sets fire to my city,” said Vimes.

“Just think of the contribution to dragon lore,” said Lady Ramkin.

“Listen, if anyone ever sets fire to this city, it's going to be me. ”

“It's an amazing opportunity. There's so many questions ...”

“You're right there.” A phrase of Carrot's crossed Vimes's mind. “It can help us with our enquiries,” he suggested.

“But in the morning,” said Lady Ramkin firmly.

Vimes's look of bitter determination faded.

“I shall sleep downstairs, in the kitchen,” said Lady Ramkin cheerfully. “I usually have a camp bed made up down there when it's egg-laying time. Some of the females always need assistance. Don't you worry about me.”

“You're being very helpful,” Vimes muttered.

“I've sent Nobby down to the city to help the others set up your headquarters,” said Lady Ramkin.

Vimes had completely forgotten die Watch House. “It must have been badly damaged,” he ventured.

“Totally destroyed,” said Lady Ramkin. “Just a patch of melted rock. So I'm letting you have a place in Pseudopolis Yard.”

“Sorry?”

“Oh, my father had property all over the city,” she said. “Quite useless to me, really. So I told my agent to give Sergeant Colon the keys to the old house in Pseudopolis Yard. It'll do it good to be aired.”

“But that area-I mean, there's real cobbles on the streets-the rent alone, I mean, Lord Vetinari won't-”

“Don't you worry about it,” she said, giving him a friendly pat. “Now, you really ought to get some sleep.”

Vimes lay in bed, his mind racing. Pseudopolis Yard was on the Ankh side of the river, in quite a high-rent district. The sight of Nobby or Sergeant Colon walking down the street in daylight would probably have the same effect on the area as the opening of a plague hospital.

He dozed, gliding in and out of a sleep where giant dragons pursued him waving jars of ointment . . .

And awoke to the sound of a mob.

Lady Ramkin drawing herself up haughtily was not a sight to forget, although you could try. It was like watching continental drift in reverse as various subcontinents and islands pulled themselves together to form one massive, angry protowoman.

The broken door of the dragon house swung on its hinges. The inmates, already as highly strung as a harp on amphetamines, were going mad. Little gouts of flame burst against the metal plates as they stampeded back and forth in their pens. “Hwhat,” she said, “is the meaning of this?” If a Ramkin had ever been given to introspection she'd have admitted that it wasn't a very original line.

But it was handy. It did the job. The reason that cliches become cliches is that they are the hammers and screwdrivers in the toolbox of communication.

The mob filled the broken doorway. Some of it was waving various sharp implements with the up-and-down motion proper to rioters.